DE2117435A1 - Process for the preparation of 3-alkyl-5-tert-butylphenols - Google Patents

Description

DIPL-CHEM. DR. ELISABETH JUNG "· MÖNCHEN 23 ^Γ Ö-APR. 19! DIPL.-CHEM. DR. VOLKER VOSSIUS cumiiimtiu ··! » DIPL-PHYS. DR. JÖRGEN SCHIRDEWAHN TELeoeAMM-Aonesse: ^ vent / monche PATENT ADVOCATE! ^{mtx fiMM}

uZ: G 043 C (Vo / kä).
Case 50 555 S.

Sumitomo chemical company, limited

Osaka, Japan

"Process for the preparation of 3-alkyl-5-tert.-butylphenols ··

Priority: April 15, 1970, Japan, Kr. 32 558/70

The alkylation of m-cresol with an alcohol, olefin or Alkyl halide in the presence of a strong acid or a Friedel-Crafts catalyst gives compounds in which the Alkyl radical selectively in the o- or p-position to the phenolic Hydroxyl group is introduced. The preparation of 3-alkyl-5-tert-butylphenols by Friedel-Crafts synthesis from m-cresol is therefore not possible.

On the other hand, it is known to m-alkylphenols by heating the. corresponding o- or p-alkylphenols to temperatures above 125 ° C in the presence of strong acids or a natural or synthetic aluminum silicate; See U.S. Patent 3,014,079. However, when this process is applied to 3-alkyl-6-tert-butylphenols, the tert-butyl group predominantly 'eliminated, and 3-alkyl-5-tert.-butylphenols are only preserved in traces.

109 145/113 *

The object of the invention was to create a process for the preparation of 3-alkyl- 5- tert-butylphenols from 3-alkyl-6-tert-butylphenols which proceeds in excellent yields. This object is achieved by the invention.

The invention thus relates to a process for the preparation of 3-alkyl-5-tert-butylphenols of the general formula I

OH

C ₄₉ ^ R _(χ)

in which R denotes an alkylreate with 1 to 3 carbon atoms, which is characterized in that the corresponding 3-alkyl-6-tert.-butylphenol at temperatures of about -10 to +70 ⁰ C with about 0.25 to 2 mol brings anhydrous aluminum chloride per mole of alkylphenol to the reaction, decomposes the aluminum complex formed with water and isolates the product.

The process according to the invention is particularly applicable to 3-alkyl-6-tert-butylphenols. When using . For example 3-methyl-6-isopropylphenol or 3-methyl-6-ethylphenol, only the starting compound is recovered and there is no rearrangement. If o-tert-butylphenol is used, p-tert-butylphenol is obtained in high yield without any significant formation of the corresponding η-isomer. When using 2-tert-butyl-4-methylphenol, the tert-butyl group is eliminated with the formation of p-cresol. If 3-l-ethyl-4-tert-butylphenol is used, there is no rearrangement of the tert-butyl group into the m-position.

109845/1935

VorzufjGV.-eisc v / ird daa erfinaunrs ^ omacse procedures for temperature from 0 to 30 C and with conversion times from 2 to 4 hours carried out at atmospheric pressure. The aluminum chloride It is preferably used in an amount of 1 I-iol per hole 3-alkyl ~ 6-tert-butylphenol used.

The 3-alkyl-5-tert-butyl phenols prepared according to the invention are valuable organic intermediates. For example, when reacting with methyl isocyanate, 3-alkyl-5-tert-butylphenol-il-methylcarbanates, which are excellent insecticides with low warm-blooded toxicity.

Bio examples explain the invention,

example 1

30 g 3-methyl-G-tert-butylphenol at 30 ⁰ C in portions with. 26 g of powdered anhydrous aluminum chloride were added. When the addition of the aluminum chloride is complete, the mixture is stirred for 2 hours at 20 to 30 ° C. and then 100 ml of water are quickly added in order to decompose the aluminum complex - ', -: ur ⁿ . Ma) i receives a very oily oil Product that fractionates dco .'- tillicvt v.'izxl. The 3> -i-i-iothyl-5-tort.-butylphenol also boils

Pri; -iul; t hnt gaßrfcT \> :. irit j ^ raj-hi .och. l '

10 9 8 A 5/19 3 5

ORiQiNAL

Connection

(I) m-Xresol 21, Q.

(II) unidentified compound (1) "" 2,3

(III) unidentified compound (2) 0.9

(IV) 3-Kethyl-5-tert-butylphenol 67, O

(V) high-boiling compounds' 8.8

Example2

30 g of 3-methyl-6-tert-butylphenol are added to Example 1 7 g of powdered anhydrous aluminum chloride reacted. The oily product obtained is fractionally distilled. You get 3-Methy1-5-tert, -butylphenol as a fraction from the boiling range 100 to 104 ° C / 2.5 Torr. .

Before the fractional distillation, the oily product has the following composition according to gas chromatography:

Connection · percent ""'

(I) m-cresol 35.2- ''

(II) unidentified compound (1) - 8.7

(III) unidentified compound (2) 0.5

(IV) 3-methyl-5 "-tert.-butylphenul 48.3 ψ (V) high-boiling compounds 7.3 '

Example ">

4 4 g of 3-eth, yl-6-tert. Butylpheru) l υ: ια -2 "6 g of powdered w" ay. ^c u? rfreles aluminum chloride are ge: uiiiis ΰαΐργήαΐ 1 to Unu ^ t ^ unr; brought. The oily product obtained is fractionally distilled. That 3-Λ "bhyl-5-te.rt.-t>ut;;.1; .jhenol boils at IV.'j up to 129 ° C /: i, 8 Torr.

1 G 9 8 45/1935

BATH ORIGINAL

Vox ·· fractional distillation has the oily product Gas chromatography has the following composition:

Connection percent

(I) 3-ethylphenol 36.3

(II) unidentified compound (1) 4.8 (III.) Unidentified compound (2) 0.2

(IV) unidentified compound (3) 0.2

(V) 3-ethyl-5-tert-butylphenol 31.5

(VI) high-boiling compounds 27.0

Example 4

g of 3-isopropyl-6-tert-butylphenol and 26 g of powdered anhydrous Aluminum chloride are converted according to Example 1 brought. The oily product obtained is fractionally distilled. The 3-isopropyl-5-tert-butylphenol also boils up to 134 ° C / 1.8 Torr.

Before the fractional distillation, the oily product has the following composition according to gas chromatography:

Connection percent

(l) 3-isopropylphenol 31.5

(IJ) unidentified compound (1) 1,8

(III) unidentified compound (2) 0.3

(IV) unidentified compound (3) 0.3

(V) 3-isopropyl-5-tert-butylphenol 25.6

(VI) high-boiling compounds' 40.5

109845/1935

Claims (3)

P a t e η t a η s ρ r ü c h e / y (_) /. Process for the preparation of 3-alkyl-5-tert.-buty! Phenols of the general formula 1 C ₄ H ₉ tert. _1 \ ¹ JR (1) in which R denotes an alkyl radical with 1 to 3 carbon atoms, characterized in that the ψ corresponding 3-alkyl-6-tert.-butylphenol at temperatures of about -10 to +70 C with about 0.25 to 2 mol of v / brings water-free aluminum chloride per mole of alkylphenol to the reaction, decomposes the aluminum complex formed with water and isolates the product. 2. The method according to claim 1, characterized in that the reaction is carried out at temperatures of 0 to 30 G. 3. The method according to claim Z _1, characterized in that the reaction is carried out for 2 to 4 hours. 109845/1935